Joyous song Lorca composed (5)
I believe the answer is:
carol
'joyous song' is the definition.
(I've seen this in another clue)
'lorca composed' is the wordplay.
'composed' indicates anagramming the letters.
'lorca' anagrammed gives 'CAROL'.
(Other definitions for carol that I've seen before include "Christmas ditty" , "Joyful song - woman's name" , "Joyful religious song" , "See 1" , "Girl" .)