I love those palms too, and really need to add some to my current landscape. I've grown them in previous gardens and really loved them. If the new fronds are coming in green and happy I wouldn't worry too much about older fronds--they do lose their oldest leaves as they age, and I always just cut them off when they look bad or yellowed. They love fertilizer so I doubt it's that, though salt build up might be a culprit, but they're pretty resistant to salt all things considered.

If the it's growing and the new fronds are coming in and expanding fine, I wouldn't worry about it too much. Let us see/hear more if you have other concerns, and let's see what our other members say too.

Take care and keep us posted!
Grant

By the look at the brown scorch, My guess is that it dried out too much during one of the 110 degree days. I usually let the yellowing fronds remain until they're brown- that way the tree can recover the nutrients that are in that frond. No big deal- it will recover.