Disagreement when liaisons initially too hard? (6,4)

I believe the answer is:

lovers tiff

I'm a little stuck... Click here to teach me more about this clue!

'disagreement' is the definition.
I don't know anything about this answer so I cannot tell whether this works.

'liaisons initially too hard?' is the wordplay.
'initially' indicates taking the first letters.
'too' becomes 'over' (I can't justify this - if you can you should believe this answer much more).
'hard?' becomes 'stiff' ('stiff' can be similar in meaning to 'hard').
The first letter of 'liaisons' is 'l'.
'l'+'over'+'stiff'='LOVERS TIFF'

'when' acts as a link.

Can you help me to learn more?

I've seen this clue in The Guardian.

Want a hint initially instead of a full solution? Install my app