translate English to French: Fixing Rosh HaShanah (New Year�s Day). The year begins on Tishri 1, which is rarely the day of the molad, as there are four obstacles or considerations, called dehiyyah, in fixing the first day of the month (rosh hodesh).
L'Encyclopédia Judaica admet ce fait dans son article à propos de la Fixation de Rosh HaShanah (Le Jour du Nouvel An).