In that case, I would say go with "status orb" over "status Orb"; also, "choice item" over "Choice item". Unless it is directly stating the specific item, such as Toxic Orb or Choice Scarf, the capitalization isn't required because it is not a proper noun. It's similar to saying something like "special stats" instead of "Special stats", since you aren't specifically stating "Special Attack" and "Special Defense". In a real life example, "I live on a street" or "I live on Main Street", but not "I live on a Street".
Edit: I would say item > orb in that case, since there are other items such as Life Orb. The term "status orb" helps to distinguish Toxic Orb and Flame Orb from other items without similar effects.