Arrive when the entertainment's finished (4,2)
I believe the answer is:
show up
'arrive' is the definition.
(I've seen this before)
'the entertainment's finished' is the wordplay.
'the entertainment' becomes 'show' (show is a kind of entertainment).
'finished' becomes 'up' (eg 'time's up' means the time is finished).
'show'+'up'='SHOW UP'
'when' acts as a link.
(Other definitions for show up that I've seen before include "Arrive - put to shame" , "Expose or keep appointment" , "Expose or appear as arranged" , "Become visible" , "Expose, or arrive as expected" .)