Time for old office worker to start (5)
I believe the answer is:
tempo
'time' is the definition.
(tempo is a kind of time)
'old office worker to start' is the wordplay.
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'office worker' becomes 'temp' (I've seen this before).
'to start' means one lot of letters go next to another.
'o' after 'temp' is 'TEMPO'.
'for' is the link.
(Other definitions for tempo that I've seen before include "Pace of a piece of music" , "Musical beat or rhythm" , "Metronome output" , "(Musically) the speed to be played" , "Time (music)" .)