There are  consistency results due to Shelah and Gorelic for the negative answer. Shelah has proved the consistency of $GCH+$there exists a Lindelof space with points $G_\delta$ of size $\aleph_2.$ See Shelah's paper ''On  some  problems  in  general  topology''. Gorelic has extended this result to get $CH+2^{\aleph_1}$ arbitrary large+ there is such a space of size $2^{\aleph_1}$.

It is also consistent with $GCH$ that there exists a Lindelof space with points $G_\delta$ of size $\aleph_\omega.$ See R. Knight's paper ''A topological application of flat morasses'', Fundamenta Mathematicae, 194 (2007) pp. 45-66.



On the other hand Shelah has proved the consistency of $CH+$ there is no Lindelof space with points $G_\delta$  of size $\aleph_2.$ See Shelah's paper ''On  some  problems  in  general  topology''.