I ask because {'ej} is a sentence conjunction, and there's no known instance of such a thing *starting* a sentence. (The non-canon {'ej HumtaH 'ej DechtaH 'Iw} doesn't count, and is in any case archaic and poetic.)

Also, {DaH} is an adverbial, and it should either start a sentence, or if standing alone, be considered an exclamation. While an exclamation is a type of sentence and I guess in principle it could be joined using {'ej}, it still sounds odd to me.  Following {'ej}, I expect {DaH} to start a complete sentence.