Excellent discovery between Jansy and Carolyn! Not much has been written about Nabokov and Cocteau;
Jansy and I have bee discussing off-list the strange inconsistency in Kinbote's age reporting: that he is 16 years Shade's junior (= b. 1914), but that King Charles the Beloved was born 1915. Perhaps this slippage is psychologically related to Kinbote's regarding Shade's "60th-no, 61st" birthday, noted already by Jansy. Very possibly others have discussed this in their articles and books, and Nab-Lers are invited to send us all to those sources! I see that the Library of America notes (ahem) tell us that "In his lecture on The Walk by Swann's Way" [...] published in Lectures on Literature, Nabokov wrote "Jean Cocteau has called the work 'a giant miniature, full of mirages, of superimposed gardens, of games conducted between space and time.'" Note 554.24-25; p. 896 in the volume. No mention of Cocteau's birthday or the coincidence there.