To the French from that time on (11)

I believe the answer is:

thenceforth

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'from that time on' is the definition.
(synonyms)

'to the french' is the wordplay.
'to the french' anagrams to 'THENCEFORTH'.
But, I am unsure how the anagram is indicated.

Can you help me to learn more?

(Other definitions for thenceforth that I've seen before include "beyond that moment" , "From that time or point onwards" .)

I've seen this clue in The Irish Independent.

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