For alcohol in Lonavala, the resort hotels are effectively the only option. Della Resorts and Fariyas Resort both have bars serving beer, spirits, and cocktails, primarily to their own guests but generally accessible to visitors eating in the hotel restaurant. Rhythm Lonavala follows the same pattern.
These are not destination bars — they are hotel bars serving Mumbai and Pune weekenders who want a drink in a comfortable setting. Prices are resort-level (notably higher than what you'd pay in Pune). On a monsoon Friday or Saturday evening they fill up quickly with weekend arrivals, so walk-in access can be difficult without a reservation for dinner.
If you're not staying at a resort and want alcohol, plan your evening meal at one of these properties and factor in the wait. Otherwise Lonavala is effectively dry.