Demand when you finish work (3)

I believe the answer is:
ask
'demand' is the definition.
(synonyms)
'you finish work' is the wordplay.
'you' becomes 'as' (I can't justify this - if you can you should give a lot more credence to this answer).
'finish' suggests the final letters.
The final letter of 'work' is 'k'.
'as'+'k'='ASK'
'when' acts as a link.
Can you help me to learn more?
(Other definitions for ask that I've seen before include "Invite (to a party)" , "Enquire" , "Pose" , "Issue invitations" , "Make enquiry" .)
