Flagellation doesn't work. Let me offer you this. Lots of French words end in -eur: amateur, poseur, auteur, etc. Where English uses -er or -or, French uses -eur: for example, "motor" is "moteur". The trigraph "eue" does not occur in French; it would make no sense.
Well, that's not much of a memory aid, but maybe it will help anyway.
I always misspell that word. I should know better by now. I will go flagellate myself for penance.