Just getting into Latin poetry.
Here’s a DACTYLIC PENTAMETER:
Vergilium vīdī tantum, neo amāra Tibullō
Tempus amīcitiae fāta dedēre meae.
The first line is supposed to a hexameter. Here’s my attempt (unsuccessful) at scanning it:
Ver-gi-li / um vī / dī tan / tum ne-o / a-mā-ra / Ti-bul-lō
In the 5th foot, the “a” should be long but it is not. Where did I make a mistake? I’m not even going to the pentameter below, because I’m still stuck with the hexameter.
Thanks!
Turns out “neo” (mistake in Bennett’s grammar from Guttenberg) should be “nec”, which changes the whole meaning and the scanning!
Ver-gi-li / um vī / dī tan / tum nec a / mā-ra Ti- / bul-lō
On to the pentameter 
It would have scanned even it were neo; the O would have been elided like this:
Ver-gi-li / um vī / dī tan / tum ne’a / mā-ra Ti- / bul-lō
Ah, good point. Thank you.
Speaking of elision though, I don’t quite understand how you can elide something and still keep the meter. In this case, the extra ‘o’ was removed so the meter would be kept, but I think elision happens a lot on an already conformant line. Can somebody elucidate this for me?
No, elision is a feature of the language that is capitalized on in poetry to force meters to work. If a line had to scan even without elision, then Vergil would have to have been drunk when he wrote litora multum ille et terris iactatus et alto.
Yes, I just had to finish reading the chapter on prosody in my textbook to see that elided vowels are not scanned at all. Thanks for the reply.