It is a transformation that has everything to do with his current way of life. The self-employed know the feeling well, the surge of adrenalin that comes with having to keep your head above water week in and week out when there are bills to pay and a family to support. Cronin is self-employed and fully recognises the effect of the fear factor.
It is what has transformed him from a rugby no-hoper to the sprightly forward who, a fortnight ago in Edinburgh, burst away to score Scotland's only try in the 22-6 victory over Canada that ended a run of nine successive matches without a win for the national side. Del Boy, as he is affectionately known, was back and in business having nudged the selectors before Christmas with an outstanding effort in Scotland A's success over South Africa.
All this could hardly be further removed from events that had left him a shambling wreck of a player two years ago. Having dirt-tracked his way round New Zealand with the Lions in the summer of '93 - the Test places occupied by his fellow Scot, Andy Reed, and England's Martin Bayfield and Martin Johnson - Cronin returned to face the music with Scotland when the All Blacks came calling in November. "The most humiliating rugby experience of my life," Cronin recalled. The 51-15 defeat was also the blackest day in Scottish playing history.
The mental scars ran deep, besides which Mother Nature exacted her own toll. Nothing new to Cronin, who fractured his spine even before taking up senior rugby and whose right knee is held in place by a staple. Last season he suffered ankle ligament problems and a pelvic injury. This Scot, surely, had reached the end of the road.
Instead, a traveller all his life, he turned the corner. The son of an army doctor who once played at Lansdowne Road for Trinity College, Cronin was born in Germany and arrived via the Netherlands to attend Campion School in Essex. From there, he became a boarder at Prior Park College in Bath, where the local club took him under their wing and shaped his playing future.
Jack Rowell, the former Bath coach and now England manager, said: "He was a No 8 at school and is quick and is one of the best jumpers in the game." David Sole, the prop first capped when at Bath and who subsequently led Scotland to their 1990 Grand Slam, also recognised the raw talent at the Rec. "It was David who asked if I had any Scottish connections," Cronin said, "and I told him my grandparents on my mother's side came from Musselburgh."
That conversation resulted in Cronin winning the first of his 30 caps, against Ireland in 1988. He is now 31 years old, though it has been a bit like starting out all over again.
This time, however, Cronin is emerging from Bourges as opposed to Bath, a lock complete with French dressing and, according to the player, a man transformed.
Cronin's "Del Boy" image was built upon a former job description of restaurant consultant. "We'd take over restaurants," he said, "turn them around and get as much money for them as possible." In France, some 120 miles to the south-west of Paris, where he moved with his wife and young son, he is pursuing a new line.
"Architectural antiques," he said. Which all sounds rather grand. "Basically, I find an old property that has seen better days, strip out the decent bits and sell them on. It's my own company in every sense because I'm the only one on the books." Visit the Tower of London and you might just find yourself taking a stroll across some cobble-stones acquired from you know who.
Better still, from a playing point of view, Cronin's lifestyle - "more wine, less lager" - has resulted in the 6ft 6in frame carrying rather less than the 16st 8lb and upwards it was once burdened with. "I've definitely lost weight, but there's more to it than that."
If you want to pick up your career, the Cronin method is worth noting, and it seems to matter little that he has made only four first-team appearances for the French Second Division side - all of them friendlies, since his playing licence has only recently been processed.
"It's this business of being self-employed, particularly when abroad. There's the family to think about and that puts you under stress. But the plus side is that it keeps you on your toes. I'm motivated again and it's showing in my play. It's no coincidence, because when I moved to Bath and then London Scottish I produced some of my best rugby for Scotland."
Bourges, apparently, is another move in the right direction for Del Boy.