So in order to complete Talisman of the Shal'dorei (collect 4 echo's of time)

Community General Discussion
1

you have to replay the raid The Nighthold and kill Elisande 4 times?
That doesn’t sound right

2

That’s correct. It then gives you the skip for that difficulty.

3

Killing a boss (or bosses) multiple times, usually 4, is pretty standard to unlock raid skips.