"Qual'è" is perfectly correct Italian. The word "qual" is outdated and can only be found in older literary works. In contemporary Italian, you can encounter it in some fixed sentences that survive from the past (notably, "qual buon vento", i.e. "nice to see you (after some time you didn't show your pretty face around)"). It goes without saying that those old "fossils of a sentence" do not have the power to dictate grammar rules of any kind, or we should review a ton of current grammar (just think of "per lo meno","mamma ha fatto i gnocchi", etc.).
Only the word "quale" is used to form new sentences in contemporary Italian, regardless of whether the following word starts with a vowel or a consonant.
Since "quale è" is correct (as confirmed by Accademia della Crusca, among others), this makes "qual'è" also correct because of elision (elisione).
One (big) problem is that the Italian school system has endorsed the "qual è" form in the past and the presence of "qual'è" has (unjustifiably) become some kind of litmus test to judge people's literacy. Because of this, whoever writes "qual'è" online may be the target of subtle (or even not so subtle) harassment. This is unfair. There are a ton of pitfalls that unschooled Italians will encounter when writing. This shouldn't be one of them because it collides with the general rule of "elisione" which can be applied without explicit permit from either Crusca or any dictionary.
I wrote an article (in Italian) about this: