about eleven o'clock
`` I can not sufficiently extol the genius with which de Hamal managed our flight . How clever in him to select the night of the fête , when Madame -LRB- for he knows her habits -RRB- , as he said , would infallibly be absent at the concert in the park . I suppose _ you _ must have gone with her . I watched you rise and leave the dormitory about eleven o'clock . How you returned alone , and on foot , I can not conjecture . That surely was _ you _ we met in the narrow old Rue St. Jean ? Did you see me wave my handkerchief from the carriage window ?