You would use an, because the word starts with a vowel sound.
No, the word "when" does not have a silent "h." The "h" sound is pronounced when saying the word.
its the letter H is silent
The "h" is silent in the word "whistle."
The letter "h" is silent in the word "hour."
The first H is silent
The letter "h" is silent in the word "honesty" because it is a silent letter. In English, there are several words where the letter "h" is silent, and "honesty" is one of them. The silent "h" is a historical remnant from the word's origin in Old French.
The silent letter in the word "honour" is the "h".
The silent letter in the word "father" is the "h."
There are no silent letters in the word "helmet".
h
the h is silent in "rhombus"
The H is silent in the word wharf. This is because the word wharf would still sound exactly the same whether it's spelled with the H or without the H.