There are both rules for Elspeth and the Carmine Dragon. You may not believe this but I happen to have a copy.
Ah, Sorry, I misread, for Age of Sigmar there is only rules for the Carmine Dragon. There is no warscroll for Elspeth, or even Battlemage on Carmine Dragon.
And I now realise the OP was looking for 8th ed rules from the Tamurkhan book.
I do wish there was a warscoll for her for AoS, as it might get me to paint mine