"Rocket Man" John
I believe the answer is:
'rocket man john' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for elton that I've seen before include "Sir ___ John, singer-songwriter" , "- John, British singer" , "One John" , "Ben --; -- John" , ". . . . . John (musician)" .)