[White Council] When the White Council attacked Dol Guldur...

[The Saucepan Man]

Well, you would have expected them to have consulted Thranduil, wouldn't you?

But I'm not so sure that they did. Didn't the attack on Dol Guldur take place during the time that Gandalf was away from Bilbo, Thorin and company, ie between their sojourn at Beorn's place and the Battle of Five Armies. Now during this time, Thranduil's folk seem to have been occupied with holding moveable feasts in the woods, capturing and interrogating Dwarves and then marching on Erebor/Dale to share in the booty under the Mountain.

So, it seems they might have been left out of that little sortie on Dol Guldur.