Can anyone explain how the cryptic clue above has the answer 'opportune'?
Let's break it down into smaller chunks:
'Work' in cryptic crosswords commonly clues the word 'OP' as in 'operation'. This (by comparison) is a shorter ('little') word.
In nautical terms, the 'left' side of a ship is known as 'PORT'.
a French female
The indefinite article 'a' for words considered feminine ('female') in French is 'UNE'
And finally, this is the definition in the clue - the word 'propitious' means 'OPPORTUNE'!