As you can see here, Thorn Scratch cannot be used for activating Needle, even if the effect deals Light damage. Tested this by mutating a Tome into a Dagger and attempting to go through the enemy several times, but it didn't count for Needle's secondary effect for some reason.
I also suspected this would be the same for Solar Spear as it has a similar interaction of "upon receiving Light damage or Fire damage", and voila, it does work as intended on this, so the problem's solely with Needle.
TL;DR
Needle's secondary effect doesn't account for 'any' Light damage source as expected, while Solar Lance does, which is odd.