Prodelision

Prodelision is a form of elision in which the latter word loses its first vowels.

Example:

"Namqu(e) etsi nullum memorabile nomen
femine(a) in poena (e)st, habet haec victoria laudem,
exstinxisse nefas." (Aeneid 2.583-585)

The "e" of "est" elides in the second line, rather than the "a" of "poena." This is very common in Latin with forms of the verb "esse."

In poetry, it can allow for the use of words in a metric form that would otherwise make their use impossible.[1]

References

1. Sidgwick, Arthur; Morice, Francis David (1885). An Introduction to Greek Verse Composition with Exercises. Rivingtons. p. 23.