Court helper with a corner in the lobby, maybe (4,3)
I believe the answer is:
ball boy
'court helper' is the definition.
(I've seen this in another clue)
'corner in the lobby maybe' is the wordplay.
'corner' becomes 'al' (I can't justify this - if you can you should give a lot more credence to this answer).
'in the' is an insertion indicator.
'maybe' indicates an anagram.
'lobby' is an anagram of 'blboy'.
'al' placed within 'blboy' is 'BALL BOY'.
'with a' acts as a link.
Can you help me to learn more?
(Another definition for ball boy that I've seen is " Tennis court attendant".)