Tom, laissé seul au début des phrases, n'arrivait pas à s'habituer à l'éloignement croissant de Mary.

English Translation

Tom, stranded alone at the beginning of sentences, couldn’t get used to the growing estrangement of Mary.

Does not make much sense in either language.

I’m guessing it’s a joke / word play about the fact that, by starting the setence with Tom, and adding subordinate clauses and other fluff, Mary ends up being farther and farther apart in the sentence.

I wonder what the names in the sentence were originally and were it came from, maybe there is more context for the joke…