Actors: pair late on in Hamlet , in Elsinore? (6)
I believe the answer is:
castle
'hamlet in elsinore?' is the definition.
'castle' can be an answer for 'elsinore?' (Elsinore is the castle in Shakespeare's Hamlet). I'm unsure of the 'hamlet in' bit.
'actors pair late on' is the wordplay.
'actors' becomes 'cast' (group of actors).
'pair late' becomes 'le' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'on' is a charade indicator (letters next to each other).
'cast'+'le'='CASTLE'
'in' is the link.
(Other definitions for castle that I've seen before include "Fort" , "Stately home in Yorkshire" , "Keep" , "Another word for chess rook" , "''An Englishman's home is his . . .''" .)