To speculate about whether Proust was a snob is as superfluous as debating the degree of Joyce’s egotism, though we could construct an argument that Proust would have been unfitted to dissect the society of Recherche without a social climber’s desire. And Joyce writing in A Portrait that the “artist, like the God of the creation, remains within or behind or beyond or above his handiwork, invisible, refined out of existence, indifferent, paring his fingernails” feels more like his defence of a narcissistic narrator than a personal attitude. Neither quality detracts from the brilliance of either writer, and arguably both characteristics are disproportionally present among writers of the time (or perhaps any time).
Both qualities are in the foreground of the story Joyce told Frank Budgen (Further Recollections of James Joyce, 1955) of being introduced to Proust at a supper party for Stravinsky and Diaghilev. “Our talk consisted solely of the word ‘No.’ Proust asked me if I knew the duc de so-and-so. I said, ‘No.’ Our hostess [although observers claim this question came from Joyce] asked Proust if he had read such and such a piece of Ulysses. Proust said, ‘No,’ And so on.”
Though the two men apparently sat beside each other and later shared a cab home, no written record exists of their encounter, though there is no shortage of biographical speculation about conversations about health and truffles.
Time's Flow Stemmed 
What year was this meeting and in whose house/salon?
On 18 May 1922, at the Majestic hotel in the Avenue Kléber, hosted by British writer Sydney Schiff and his wife Violet, to mark the premiere of Stravinsky’s ballet Le Renard, performed by Diaghilev’s Ballets Russes.
Richard Davenport-Hines has written of it in Night at the Majestic: Proust & the Great Modernist Dinner Party of 1922, though it is also well documented elsewhere, though with wide variances.
Coming back to this today – a bit late – but I asked because I’m very interested in this time period, and the “meetings” of various writers. Mainly because of Ramuz, but also for Julia Daudet. When I was in New York the week before last, I got the chance to look at one of Daudet’s journals at the Morgan. It was very hard to read and I wish I’d had more time with it, but she is one who meticulously recorded these kind of events, and with much of the same people. (Her son, Lucien, was one of Proust’s closest friends and, as legend has it, she was one of Proust’s first readers for Recherche). She is someone I’d like very much to translate. She has a Notes sur Londres that must be fascinating, if I could just get my hands on it 🙂
What is odd is that neither Proust nor Joyce wrote anything of the event, in Joyce’s case probably because he was so pissed he remembered little, if anything, of it the day after.