The respondent in the JC asked one of London's most distinguished Spanish-Portuguese scholars, the Rev. David Aaron de Sola about it, and he replied that he doesn't think Illowy is correct. Instead of Esnoga being derived from אש נוגה ,אש נוגה was derived from Esnoga. de Sola explained how Esnoga comes from Synagoga, and has a Spanish prefix. He explains that "the E is constantly added by Spaniards to words of foreign origin, especially if they commence without a consonant." He is quite correct, although evidently he didn't understand the reason why, which is that Spanish doesn't allow initial consonant clusters, so out of necessity a vowel prefix was added.