〜ともなると／〜ともなれば

社長ともなると、責任が重いです。

Shachō to mo naru to, sekinin ga omoi desu.

Once you become president, the weight of responsibility tells.

ともなると draws what necessarily follows from reaching that station

週末ともなれば、この道は混みます。

Shūmatsu to mo nareba, kono michi wa komimasu.

Come the weekend, this road jams up.

The first term is a special time or station, not an ordinary thing

条件形よりも重みがあります。

Jōkenkei yori mo omomi ga arimasu.

It carries more weight than an ordinary conditional.

It implies a known inevitability, not a mere hypothesis