Make whole new lesson about overture to Hebrides — that was his (11)
I believe the answer is:
mendelssohn
'was his' is the definition.
The definition suggests a singular noun which matches the answer.
'make whole new lesson about overture to hebrides' is the wordplay.
'make whole' becomes 'mend' (I've seen this in another clue).
'new' is an anagram indicator.
'about' means one lot of letters goes inside another.
'overture to' indicates taking the first letters (overture can mean the beginning of something).
The first letter of 'hebrides' is 'h'.
'lesson' is an anagram of 'elsson'.
'elsson' going around 'h' is 'elssohn'.
'mend'+'elssohn'='MENDELSSOHN'
'that' is the link.
Can you help me to learn more?
(Other definitions for mendelssohn that I've seen before include "German composer, Felix, d. 1847" , "Elijah composer" , "German romantic composer of orchestral and choral works, d. 1847" , "German composer of The Hebrides, d. 1847" , "Wedding March composer" .)