Provider of a rondo arrangement (5)
I believe the answer is:
donor
'provider' is the definition.
(thesaurus)
'a rondo arrangement' is the wordplay.
'arrangement' is an anagram indicator.
'rondo' anagrammed gives 'DONOR'.
'of' acts as a link.
(Other definitions for donor that I've seen before include "One giving to a cause" , "One who dishes out" , "Philanthropist" , "blessed person, relatively" , "A giver, often of blood" .)