French language Q&A Forum

From a quiz on usage of "quand" and future tense:

Question was:

Quand ils ________, tu iras les accueillir. .When they arrive, you will go and welcome themand correct answer given was "arriveront".However, I wonder if the futur antérieur would be more appropriate? They have to arrive before you can go meet them, right?So how about:Quand ils seront arrivés, tu iras les accueillir.

- i was told that it is always autour DE (by a french conversation teacher),  Is this something that is so commonly used incorrectly that it has become acceptable over time? (in one of your examples, and in others from other sites, it is autour DE LA lune, or autour DU monde.)