Changing size of top label when using levelplot for array

I've plottet some data from a 3-dimensional array using levelplot().The 1st&2nd dimension names (dimnames()) are used as tick marks on the x- and y-axis, while the 3rd dimension name is displayed in a light-orange box on top of the graphs. How do I change the size of the text in this box?

Here is what I have so far:

> X<-array(runif(27,1,10),dim=c(3,3,3))
> dimnames(X)<-list(c("yesterday","today","tomorrow"),c(1:3),c("Elephant","Cat","Penguin"))
> levelplot(X)

I want Elephant, Cat and Penguin to be larger. I tried manipulating scales, main.text.cex and even looked into the properties of the plot to find my 3rd-dimension labels in a list called condlevels$Var3.

Because you faceted the plot, it's one of the paramters under strip, so do:

levelplot(X,par.strip.text=list(cex=2))