I've seen on several web sites that the Helbronner portion of the lifts in Chamonix is only open June - August. The 2015 RS guidebook includes the reference to this lift in the overall Aiguille du Midi section, so it's difficult to determine if the months/hours mentioned include Helbronner (May - Oct) or are just for Auguille du Midi (and the 2013 book specifies Helbronner was only June - Sept for that year).
Can anyone provide any info? We would prefer to schedule a stop in Chamonix when the Helbronner lift is open (understanding weather conditions can close it at any time), so if it's not open in late May, then we'd prefer to wait until another trip.
Thank you!