They are in Ravenloft Wilderness Area, far to the east.
https://ddowiki.com/page/Flameskull
They always surprise. There are always more than 1, sometimes 4! come at you from every direction.
Before or during their attacks I buff with Mage Armor, Shield, Blur, Protection from Elements, Stoneskin, Displacement, and Tensor's Transformation. I am a 1st lifer Lvl 14 DPS EK Sorc with a buffed AC of 68, 248 HP, 6% Dodge, 34 PRR & MRR, 26 Spell Resistance, +5 Spell Saves, + 5 Resistance, +17 Reflex Save, and 1800 SP. They still kick my butt!
I find Flameskulls more difficult to fight than a Beholder. Beholders I always knock off from a distance with a ray spell before they even see me. I got a high spot which helps.
Any recommendations on tactics or otherwise?