LLDB does not appear to be reading my .lldbinit file on startup

I have a file ~/.lldbinit with a single alias:

command alias pi print (int)

But when I run my app from Xcode, the alias does not work. However, if I manually enter the alias, then the alias does work:

(lldb) pi 6
error: 'pi' is not a valid command.
(lldb) command alias pi print (int)
(lldb) pi 6
(int) $3 = 6
(lldb) 

This leads me to suspect that my .lldbinit file is not getting read. Or is there a different problem that I am missing? Can anyone help?