Promotional work to bring joy to church dignitary (7)
I believe the answer is:
prelate
'church dignitary' is the definition.
(I've seen this before)
'promotional work to bring joy' is the wordplay.
'promotional work' becomes 'PR' (public relations).
'to bring joy' becomes 'elate' (I've seen this before).
'pr'+'elate'='PRELATE'
'to' acts as a link.
(Other definitions for prelate that I've seen before include "priest" , "Senior member of the clergy" , "High-ranking clergyman" , "Church high-ranker" , "Bishop perhaps" .)