The package provides commands \makefirstuc that uppercases the
first letter in its argument (with a check for a semantic
markup command at the start of the argument), and \xmakefirstuc
which expands the argument before uppercasing. It also provides
\capitalisewords{phrase} which applies \makefirstuc to each
word in the phrase, where the words are separated by regular
spaces. (Exceptions can be made for words that shouldn't be
converted.)