To begin with, Edward Elgar composed to entertain (6)
I believe the answer is:
regale
'entertain' is the definition.
(thesaurus)
'to begin with edward elgar composed' is the wordplay.
'to begin with' says to take the initial letters.
'composed' indicates an anagram.
The initial letter of 'edward' is 'e'.
'e'+'elgar'='eelgar'
'eelgar' with letters rearranged gives 'REGALE'.
'to' is the link.
(Other definitions for regale that I've seen before include "Entertain with conversation" , "Feed or entertain well" , "Entertain, delight" , "Generously entertain (with)" , "Entertain with stories" .)