A tenor arrangement is over-elaborate (6)
I believe the answer is:
ornate
'over-elaborate' is the definition.
(I've seen this before)
'a tenor arrangement' is the wordplay.
'arrangement' is an anagram indicator.
'a'+'tenor'='atenor'
'atenor' anagrammed gives 'ORNATE'.
'is' is the link.
(Other definitions for ornate that I've seen before include "Lavishly decorated" , "Excessively decorated" , "Rococo" , "Heavily decorated" , "Over-decorated" .)