Is it possible to do start iterating from an element other than the first using foreach?

Yes. Do the following:

Collection<string> myCollection = new Collection<string>;

foreach (string curString in myCollection.Skip(3))
    //Dostuff

Skip is an IEnumerable function that skips however many you specify starting at the current index. On the other hand, if you wanted to use only the first three you would use .Take:

foreach (string curString in myCollection.Take(3))

These can even be paired together, so if you only wanted the 4-6 items you could do:

foreach (string curString in myCollection.Skip(3).Take(3))