Nouns ending in -elle are usually feminine.
The suffix often forms a diminutive feminine.
Is mademoiselle masculine or feminine?
lamademoiselle
The rule behind it
95.1% of -elle nouns are feminine
In context
Est-ce que tu sais où Mademoiselle Hudson habite?
Do you know where Miss Hudson lives?
Mademoiselle Klein fait passer un test chaque vendredi.
Miss Klein gives a test every Friday.
Mademoiselle March m'a donné un dictionnaire anglais.
Miss March gave me an English dictionary.