At trick 2 Dummy's ♣3 is lead to Declarer's ♣J,which loses to the ♣K of North.
But whatever North now leads at trick 3 it does not matter, North will regain the lead and make his required 9 tricks for the 3NT contract.

PS
North must under no circumstance lead and win his ♦A at trick 3, for that will present Declarer with an extra trick with the ♦K !
North must be patient. As long as he keeps his ♦A, Declarer can not make a trick with his ♦K !