Plot hole: If Richard never reveals to Elise he is from the future, how then does the old Elise know where and when to find Richard to give the watch to and create a time loop?
Suggested correction: I agree this is not explicitly explained in the film. But because Elise was an actress, it's not a stretch to imagine that she would still follow the theater news, see the announcement of Richard's new hit play in 1972, recognize him, and go to the premier party to give him the watch.
Character mistake: According to her biography found in the library, Elise was born November 11, 1885, but William Robinson tells Richard that he met Elise when she was 16 years old, in March, 1903, at which time she would have been 17.
Factual error: When Richard Collier follows Elise into the restaurant all the men are wearing hats. Their hats would have been checked at the door.