Cultural differences have changed the spelling to suit different dialects. The primary spelling is hors d’oeuvres.
This is because the primary use of hors d’oeuvres in the Middle Ages related to the concept of dishes as entertainment.
To entertain guests, nobles would present hors d’oeuvres to the communal table that sometimes featured animals emerging from pie crusts or other dishes.
French cuisine and French wine became indelibly associated with aristocratic cooking styles in the English-speaking world from the Middle Ages on.