Difference between Il and Io
What's the difference between the following (Both are male and can be used with objects):</pre>
Dov'è il libro?
Once you know that the noun is male, you use:
L' before vowels (truncation of lo)
LO before impure s (i.e. s+consonant), pn, gn, ps, x, y, and z
Note that "before" here means exactly that, i.e. it only depends on the following letters and not on the noun the article refers to: to use your example "il mio stadio", "lo strano libro".