In reply to Philb1950:
I've climbed it twice. First time via the rognon above the arete and the second time by going round to the left. It is significantly easier if you avoid the rognon. Indeed I would not argue with anyone who considered it to be TD if the rognon is climbed as it has a couple of pitches of HVS/E1.
With regard to the OP I did it in August the first time and the end of September the second time but both of these were a very long time ago and conditions may have changed. On the first ascent the ridge was a case of 3 steps forward and 2 steps back as the snow was soft (In retrospect it was probably out of condition but we knew no better)but the top of the ridge flattened out into very hard ice and may well have been Grade 4. It slowed us down so much we had an unplanned bivi. The second time was perfect neve all the way and we were up and down by late afternoon.
Post edited at 13:32