If the subject of a clause is a noun, then the construction of the inversion is a bit more complicated.
The noun itself stays at the beginning, then comes the conjugated verb and an additional pronoun is added to it. This way a backward-reference to the noun is made.
Pierre a perdu son
argent. => Pierre a-t-il
perdu son argent?
Pierre has lost his money. => Pierre, has he lost his money?
a dit des bêtises. => Le président
a-t-il dit des bêtises?
The president said nonsense. => The president, did he say nonsense?