there really is no “official” english form for any Hebrew name. there is no “proper” translation. there is for some names a particular english abberation of the Hebrew name which is more common and thus more accepted by the non Jewish world. generally this has come about because that’s how the name was mispronounced by the translators of the “new” testament. art scroll generally uses those mistranslations in their english versions. that always bothered me but im sure they have their reasons. i would much prefer to see Avrohoms son be translated as Yitzchak than Isaac.