And in all such expressions as: o|cio|so é | i|rri|ta|do, Se|vi|lla | ú O|vie|do, etc.
Except when a vowel is repeated:
Si he es|cu|cha|do | cuan|do ha|bla|bas.
(Calderón, No hay burlas con el amor, III)
In modern Spanish, h, being silent, has no effect, but in older Spanish, h for Latin f, being then pronounced, prevented synalepha, as in:
Por | el | mes | e|ra | de | ma|yo
cuan|do | ha|ce | la | ca|lor.