Hi Carcam,
You are correct, and I've had the same debate. I've anticipated your question, as Google Translation is not incorrect as it do not follow French recommandation from 1990's rules...
FYI, I'm writing "évènement" since years...
Both are OK, but "événement" is the old "French" writing (wrong pronunciation) which has been corrected by 1990's writng rules.
French Accademy recommands "évènement" which is a much better French speaking...
I hope Google Translation will adapt and correct to French's 1990's reform... Soon !
So :
"évènement" is the correct writing (now), "événement" has became an acceptance.
We have many French words that has moved to : « collége » >> collège ; « siége » >> siège ; « Liége » >> Liège ; « j’abrége » >> j’abrège ; etc. Accent é è ê ë are our French mysteries...
See articles :
https://www.projet-voltaire.fr/culture-generale/evenement-evenement-orthographe-accent-aigu-grave
https://www.dictionnaire-academie.fr/article/A9E3137
https://www.joomla.fr/evenements (see our French Joomla colleagues)
It's your decision to confirm, but
I would move to "évènement" current French !
You may explain this French trick in an dedicated article, as I'm not good enough English speaker.
Best regards,
Gil