Its is considered hardy to maybe 10F under desert conditions. That means it should be dry at the roots, low humidity, and somewhat shrivelled which increases frost resistance. In practice you should keep it much warmer than 10F, frost free might be best for a newly potted and watered plant. The orange spots may be frost damage or they may indicate a pest problem such as spider mites. The mites might be gone now and you are just noticing the scarred skin. Frost damage tends to be black and will go mushy. It is even possible that you are seeing sun scorch if the plant has been inside a dark store for a while. It will flower best with a cold and dry period in winter, but try to keep it somewhere like a porch for this winter at least. Even a garage would be good, it doesn't really need much light if it is kept cool enough because it won't grow. Make sure you get it used to bright light gradually in spring. More general care is easy. Plenty of sun in summer but some afternoon shade if you are in a desert area. A big plant like your's will not need watering very often, water deeply and then allow to dry out. It won't need watering at all during winter, even though it may shrivel quite a bit especially if it is exposed to freezing conditions. Use a dilute fertiliser a few times a year, or a very dilute fertiliser with every watering, producing those massive flowers can really take it out of a plant ;)

I can't say as I've noticed any fragrance from the flower; that's the first thing I checked for, actually. When my E. calochlora flowered, I remember that bloom having a nice scent. I'm also allergic to tree pollen this time of year, so I probably can't tell either way at this point. It would really be interesting to experience the scent of this species' bloom; maybe next year I can have the plant inside so I don't get such bad allergic reactions! :)

cactusmharris: Yes, I was taught that 'C' is always hard, but slightly softer when it precedes 'h'. The 'S'-sound (in front of certain vowels) was introduced during the late antique period and became the standard in medieval Latin. At first it felt weird to always use the 'K' sound, but once I got used to it I actually found it easier. Of course, since botanical Latin was developed much later, the more modern pronunciation is far more common, especially as the pronunciation of the Latin words that still exist in many Western languages is based on the modern rules. mastemot: I think you will have to wait for quite some time. I don't know exactly how big/old they must be, but I have only seen flowers on much bigger plants (this is one reason why I don't grow cereoids). BTW, it is the red spines on your N. scopa that I envy, I once had one that I accidentially killed, and I have not yet found a replacement, most plants have only white spines :-(.

Oh wow. Just as nice guess am to wait till its flowered. From images I have seen of both of these they very old several decades old ones are tall. So maybe mine is much older. At moment it's on a window cil that gets morning sun, and has a cold draft. But if we're right then it's a hardy. Cacti. So draft doesn't mater. But I've now stopped watering it was going to water again when daffodil flowers open. (March/April)