either

Sveiki atvykę į Grenoblį! (welcome having come to Grenoble)

or
Sveiki Grenoblije! (Welcome in Grenoble)

make sure you're viewing trough Baltic encoding/character set, Baltic (Windows), if yo have Windows.

The first one is what you would WRITE on a sign, the second one is what you would SAY to a person. This is in You formal and also you all form, which is highly recommended for someone you don't personally know. You familiar form would be "sveikas (atvykęs)..." for masculine, and "sveika (atvykusi)..." for feminine
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