LSt.13:4 :ܕܠܗ݀ܘ ܕܐܝܬ ܠܗ ܐܡܬܝ ܕܢܟܦܢ‏ : (the right time to eat) for the one who has (food) is whenever he gets hungry
See the entire entry for ˀimmattī, ˀimmaṯ conj. when, whenever