According to PlanB, as you can read on my
June Report, halvening isn't having any measurable impact on Litecoin price, as opposed of what is happening for bitcoin.
Regarding the Litecoin overperforming BTC, welol, I can't see all this evidence:

Long gone are the days when LTC was "silver to Bitcoin Gold" or "Testbed for Bitcoin".
Now LTC is like every other shitcoin.
Except Litceoin massively outperformed the rest of the altcoin market recently. Look at the December-March period where it totally outperformed Bitcoin, too. This is the reason people started speculating the bull run was being driven by the LTC halving, because LTC's momentum was so strong.
As it turned out, too many people bought into the halvening hype and it didn't play out, but LTC was a great hold through Q1.