What is This Grammatical Practice?
I'm listening to some basic audio lessons. They have been using phrases where the Italian word "lo" is placed after a verb and contracted with it e.g. Non posso travarlo (I cannot find it). I'm a bit confused because sometimes the "lo" is placed before the verb e.g. Lo voglio addesso (I want it now). Please can someone tell me the names of the grammatical constructions in use here so that I can look them up?

Question

What is This Grammatical Practice?
I'm listening to some basic audio lessons. They have been using phrases where the Italian word "lo" is placed after a verb and contracted with it e.g. Non posso travarlo (I cannot find it). I'm a bit confused because sometimes the "lo" is placed before the verb e.g. Lo voglio addesso (I want it now).  Please can someone tell me the names of the grammatical constructions in use here so that I can look them up?

Answer

"Forma proclitica" (before the verb) and "forma enclitica" (after the verb and attached to it).

Answer

Grazie Maria Luisa. I wish my Italian was good enough to fully appreciate what you were kind enough to write. I think you are saying that direct object pronouns appear before the verb unless they are being used with the infinitive form of the verb. In that case they are placed afterwards and contracted. Correct?

Answer

"LO" è una particella pronominale che si usa quando abbiamo un verbo all'infinito preceduto da un  verbo servile (potere, dovere, volere, sapere)

Non posso trovarLO.  
Analisi Logica: IO non posso trovare (che cosa?Compl. ogg. -> LO) 
In questo caso svolge la funzione del complemento oggetto.

Differentemento: "LO voglio adesso" non presenta nessun verbo all'infinito.
Per usare LO come sopra, dovremmo scrivere: IO voglio trovarLO adesso.

Answer

They are unstressed clitic pronouns. They are placed before the verb in definite moods, but imperative. They are placed after the verb and linked in the imperative and indefinite moods (infinitive, gerund, participle).
"Non LO trovi? cercaLO meglio! se dovessi trovarLO io (also: "se LO dovessi trovare io), me LO terrò"
With modal verbs, they can indifferently be placed before the modal or after and joined to the infinitive.