Definitions for "Elision"
the connection of two phrases so that the cadence of one overlaps with the beginning of another.
Lat. "knocking out." The practice of omitting certain syllables during scansion. A final syllable ending in a vowel (or the letter -m) is normally elided before a word beginning with a vowel (or an h-).
Elision makes two syllables occupy a single metrical position. Normally elision happens "where there is an unstressed vowel before a consonant or where one syllable ends with a vowel and the next begins with one ('the other')" (Poetry in English 1166). See Example 20.