Lorna likes men and women with time to make an expected contribution (2,4,3)
I believe the answer is:
do ones bit
'make an expected contribution' is the definition.
(to do one's bit is to do what's expected)
I can't explain the rest of the clue.
(Other definitions for do ones bit that I've seen before include "muck in" , "Contribute fairly for the common good" , "to perform as required" , "Take on a fair share" , "Play one's due part" .)