I was hoping to find an answer exactly in this post.
But as it was not here I first had to find it:
viewtopic.php?p=7026-archived-italian-f ... t=Lo#p7026
The following is an excerpt from this embedded link
https://www.thoughtco.com/italian-defin ... es-4055936
Masculine nouns do NOT get the articles il and i but rather lo and gli when they begin with a vowel. For example, the noun albero, or tree, is masculine and it begins with a vowel; its article is lo; in the plural, alberi, its article is gli. Same for the following:
L(o)' uccello, gli uccelli: the bird, the birds
L(o)' animale, gli animali: the animal, the animals
L(o)' occhio, gli occhi: the eyes, the eyes
...
Also, masculine nouns take the articles lo and gli when they begin with the following:
s plus a consonant
ps and pn
gn
x, y, and z