The French didn't let their beloved Jerry Lewis down this weekend, pledging nearly $33 million during his first overseas telethon. Organizers said Sunday that donations were four times greater than their expectations and as successful as recent U.S. telethons to raise funds for research into muscular dystrophy. The largest check was for the equivalent of $50,000 and the smallest for $2--the savings of an unemployed youth. The telethon began Friday night on the Antenne 2 network, ending 29 hours later, at 1 a.m. Sunday. Most of the pledges were made by telephone, though some were contributed through Minitel, the French home computer system.