Back again with more questions. Since I've got pumped up about learning to grow orchids I puchased a couple of cattleyas from a reputable orchid grower here in Florida about three weeks ago. They arrived looking well and healthy but I decided to repot them because they were in really small plastic pots. They seem to be doing OK but just recently what appears to be the first issue, or maybe it's the first seeding,

Name:  New Cattleya.jpg
Views: 1840
Size:  195.7 KB

Name:  New Cattleya 1.jpg
Views: 1305
Size:  196.9 KB

of one of them has turned yellow. Is this normal or is this something to be concerned with? I know that with my dendrobium the lower leaves often yellowed and fell off.