It appears, from the reviews on the Arc'teryx website, that people have pretty mixed reviews concerning these gloves, but a general consensus is that they aren't particularly warm. For instance, one person said that they were "flexible, well built but cold."
People discuss usage in temperature ranges, asserting a number of opinions, but overall, the impression that you end up with is that they would perform decently in temps as low as 10 degrees Fahrenheit (~ -12 degrees Celsius), but one person stated that conditions colder than 25 degrees Fahrenheit result in chilly hands for the user. Another gentleman, while discussing his summit trip of Mt. Rainier, says that "[a]bove 13,000' with 20-30mph winds, snow and temps well below freezing my hands did get chilled," but goes on to say that these are intended more for backcountry outings than expedition-status trips.
These are meant, as one member of the Arc'teryx staff states in an answer to the user, "for cold and wet conditions where you need ultimate dexterity. If you are looking for a glove for really cold temperatures, the Zenta AR gloves are going to be warmer."
In summation, these would probably be good if you don't intend on facing prolonged temperatures in the single digits or teens (brief periods of exposure and endurance, probably, but nothing extended). However, if you expect to encounter excessively gelid situations where you need maximum warmth, these may not be ideal.
Hope this helps! Also, check out the Zenta ARs if warmth is your goal.