u precedes it, or i follows it.

Ex. _Fuí diestro, fuí valiente, fuí arrogante_. Cervantes.

When u is the middle vowel there may be synalepha if i follows it. The
construction is very rare.

There is no synalepha with a word beginning with hue.

Ex. _Mucho nuestro huesped tarda_. Tirso de Molina.

In the following cases the groups of vowels which would usually make
triphthongal synalepha are pronounced in two syllables:

(1) When the first word of the group ends in two vowels which do not
form a diphthong.

Ex. _Que aún tení|a^abiertos_, p. 187, LXXIII, l. 2.

(2) When the two initial vowels of the second word do not form a
diphthong.

Ex. _Tú, sombra^a|érea que, cuantas veces_, p. 170, XV, l. 7.

(3) When the first word ends in a diphthong and the second begins with
a vowel in a constituent syllable (i.e. a syllable on which the
rhythmical accent falls).

Ex. _Tan gran designio honra tus audacias._