>>>>It's the same in English- the indefinite article a becomes an before a word starting with a vowel.
>>>>
>>>> For u it depends how it is pronounced - I think
>>>>
>>>>A U-Turn
>>>>An unrelated matter
>>>
>>>On a related note, same goes for words beginning with an aitch - "an honorable exception".
>>
>>Yes, it depends on whether the h is pronounced
>>not pronouced: an honorable exception
>>
>>pronounced: a house
>
>But of course. This is English, it doesn't have rules, it has lists.

To be fair - I think all languages have lists

Same in French a word starting with an H

You have to know whether the h is kind-of-pronounced or not

l'homme but le hibou

I think if the noun has latin origin then it is not pronounced, if it has german/english roots it is vaguely pronounced

http://fr.thefreedictionary.com/h+aspir%c3%a9