How is hamzat-al-wasl pronounced at the beginning of an ayah?
I know that at the beginning of a noun, when the *hamzat-al-wasl* in the definite article الْ is pronounced, it is always pronounced as "al-" (i.e. with a *fatha*). However, using [Al-Fatihah 6](http://quran.com/1/6) as an example, the *hamzat-al-wasl* in اهْدِنَا is pronounced "ihdinaa" (i.e. with a *kasra*).Visually, there is nothing to distinguish the *hamzat-al-wasl* in either case; they are both written exactly the same. How should one know which vowel to pronounce when the *hamzat-al-wasl* comes at the beginning of an *ayah* (i.e. is not absorbed into the preceding vowel), or is it just a matter of learning and memorizing how each word would be pronounced when it comes up?