I say that leading up to his book, A History of the Arab Peoples, and what it had to say about the Armenian Holocaust. In a word, nothing. He did mention something that hinted that there might have been a few problems, but genocide or holocaust, no. Here is how he dealt with the event commemorated today,
“This was shown in the 1890's, when nationalist parties in another Christian community, the Armenians, began to work actively for independence the Ottomans were able to suppress the movement with great loss of life, and without effective European action,...” p. 280From his point of view it was just another example of how Muslims have responded to Christians through the ages. 1890 is a bit early. I would guess that the serious attempts to kill Christians were put off until the world was distracted by World War I.
As with the Jewish Holocaust, never forget.
Hourani, Albert. A History of the Arab Peoples. Cambridge: The Belknap
Press of Harvard University Press, 1991.
homo unius libri