Nigel in Reform welcomes unusual form of protection delivering sorrowful lines (9)

'protection delivering sorrowful lines' is the definition.
I can't judge whether this defines the answer.

'nigel in reform welcomes unusual form' is the wordplay.
'in reform' indicates an anagram (I've seen this in other clues).
'welcomes' is an insertion indicator (in sense of 'invites in').
'unusual form' becomes 'egis' (I can't justify this - if you can you should give a lot more credence to this answer).
'nigel' with letters rearranged gives 'eling'.
'eling' going around 'egis' is 'ELEGISING'.

'of' acts as a link.

Can you help me to learn more?